Everyone who has ever traveled through the southern Appalachian Mountains in late spring is familiar with the breath-taking colorful beauty of the flame azalea (Azalea calendulaceum) when it is in full flower. Although plant hunters have searched the far corners of the earth for rare and beautiful shrubs for our gardens, this native azalea can still be placed at the top of any list of shrubs with brilliant spring blooms.
Like other azaleas and rhododendrons, it requires an acid soil where hemlocks, pines and oaks abound, as well as a normal amount of soil moisture. Given these two requirements, there is little else this ornamental azalea demands. Normally it grows no higher than 9 feet.
Fortunately for gardeners, the color of the flowers varies from a light yellow to a rich orange red. Most plants will have orange flowers, but where hundreds of seedlings are grown, the other colors will crop up. Commercial propagators long ago realized the value of the yellow and reddish-flowered clones and began to propagate them asexually.
Propagating the flame azalea is best done by seed, which ripens in the dry capsules in the fall. It is cleaned and kept dry until early spring, when it is sown on a very fine layer of moist sphagnum moss. Propagation by cuttings is extremely difficult and is best left to the experienced commercial propagator.
The flame azalea blooms with some of the mock-oranges, beauty-bush and arrow-wood (in early June in New England). Its most important feature is its ability to retain its flowers in good condition in full sunshine for almost two weeks.
Since few azaleas bloom this late in the spring, the flame azalea is valued in extending the flowering sequence of this colorful group.
Occasionally, though not always, the flame azalea foliage may have a rich reddish tinge in the fall. lt is easy to prune and care for if given a good start in the right kind of soil.